A hybrid vehicle efficiently combines two or more kinds of different power sources with each other, for example, an engine obtaining a torque by burning fuel (fossil fuel such as gasoline, or the like) and an electric motor obtaining a torque by electric power of a battery.
A general hybrid vehicle includes a high voltage battery, a battery management system (BMS), a motor, a motor control unit (MCU), an inverter, and a main relay.
Particularly, the high voltage battery has functions of supplying electrical energy required for assisting the motor at the time of accelerating the hybrid vehicle and storing electrical energy generated by regeneration of the motor at the time of decelerating the vehicle or generation of an engine margin output therein.
In order to perform above functions of the battery, the battery management system (BMS) measures a current, a voltage, a temperature, and the like, of the battery to calculate a state of charge (SOC) of the battery, maximum available charging power Pin and discharging power Pout, and the like, and transmits information on the SOC, the charging power, and the discharging power to a vehicle control unit such as an engine control unit (ECU). The ECU performs a control for the highest performance of the hybrid vehicle through distribution of power of the engine and the motor using the information on the SOC, the charging power, and the discharging power.
Here, the battery management system (BMS) may erroneously calculate a real SOC of the battery due to an error or the like. The battery management system (BMS) has a function of resetting the SOC of the battery in accordance with the real SOC of the battery. However, the current battery management system (BMS) has a problem that the SOC of the battery is reset regardless of whether or not the vehicle is driven or starts up.